Literature References: A colorless substance found in the wings of butterflies (especially of white-winged butterflies). May be obtained from xanthopterin by dehydrogenation: Wieland, Purrmann, Ann.544, 172 (1940). Synthesis by fusing 2,4,5-triamino-6-hydroxypyrimidine with an excess of oxalic acid: Purrmann, ibid. 188. See also ref under Xanthopterin and review on pterins by Purrmann, Fortschr. Chem. Org. Naturst.4, 64 (1945).